7,162 research outputs found
The effect of moisture on cellulose nanocrystals intended as a high gas barrier coating on flexible packaging materials
Cellulose nanocrystals (CNCs) exhibit outstanding gas barrier properties, which supports their use as a biobased and biodegradable barrier coating on flexible food packaging materials. As highly hydrophilic biopolymers, however, CNCs have a strong sensitivity to water that can be detrimental to applications with fresh foods and in moist conditions due to the loss of barrier properties. In this work, the oxygen and water vapor permeability of polyethylene terephthalate (PET) films coated with CNCs obtained from cotton linters were measured at varying levels of relative humidity, both in adsorption and desorption, and from these data, the diffusion and solubility coefficients were estimated. Therefore, the characterization of CNCs was aimed at understanding the fundamentals of the water-CNCs interaction and proposing counteractions. The CNCs' moisture absorption and desorption isotherms at 25 \uc2\ub0C were collected in the range of relative humidity 0-97% using different techniques and analyzed through GAB (Guggenheim-Anderson-de Boer) and Oswin models. The effects of moisture on the water status, following the freezable water index, and on the crystal structure of CNCs were investigated by Differential Scanning Calorimetry and by X-ray Powder Diffraction, respectively. These findings point to the opportunity of coupling CNCs with hydrophobic layers in order to boost their capabilities as barrier packaging materials
Cardiovascular Dysfunction Criteria in Critically Ill Children: The PODIUM Consensus Conference
CONTEXT
Cardiovascular dysfunction is associated with poor outcomes in critically ill children.
OBJECTIVE
We aim to derive an evidence-informed, consensus-based definition of cardiovascular dysfunction in critically ill children.
DATA SOURCES
Electronic searches of PubMed and Embase were conducted from January 1992 to January 2020 using medical subject heading terms and text words to define concepts of cardiovascular dysfunction, pediatric critical illness, and outcomes of interest.
STUDY SELECTION
Studies were included if they evaluated critically ill children with cardiovascular dysfunction and assessment and/or scoring tools to screen for cardiovascular dysfunction and assessed mortality, functional status, organ-specific, or other patient-centered outcomes. Studies of adults, premature infants (≤36 weeks gestational age), animals, reviews and/or commentaries, case series (sample size ≤10), and non-English-language studies were excluded. Studies of children with cyanotic congenital heart disease or cardiovascular dysfunction after cardiopulmonary bypass were excluded.
DATA EXTRACTION
Data were abstracted from each eligible study into a standard data extraction form, along with risk-of-bias assessment by a task force member.
RESULTS
Cardiovascular dysfunction was defined by 9 elements, including 4 which indicate severe cardiovascular dysfunction. Cardiopulmonary arrest (>5 minutes) or mechanical circulatory support independently define severe cardiovascular dysfunction, whereas tachycardia, hypotension, vasoactive-inotropic score, lactate, troponin I, central venous oxygen saturation, and echocardiographic estimation of left ventricular ejection fraction were included in any combination. There was expert agreement (>80%) on the definition.
LIMITATIONS
All included studies were observational and many were retrospective.
CONCLUSIONS
The Pediatric Organ Dysfunction Information Update Mandate panel propose this evidence-informed definition of cardiovascular dysfunction
Search for GeV Gamma-ray Counterparts of Gravitational Wave Events by CALET
We present results on searches for gamma-ray counterparts of the LIGO/Virgo
gravitational-wave events using CALorimetric Electron Telescope ({\sl CALET})
observations. The main instrument of {\sl CALET}, CALorimeter (CAL), observes
gamma-rays from GeV up to 10 TeV with a field of view of nearly 2 sr.
In addition, the {\sl CALET} gamma-ray burst monitor (CGBM) views 3 sr
and sr of the sky in the 7 keV -- 1 MeV and the 40 keV -- 20 MeV
bands, respectively, by using two different crystal scintillators. The {\sl
CALET} observations on the International Space Station started in October 2015,
and here we report analyses of events associated with the following
gravitational wave events: GW151226, GW170104, GW170608, GW170814 and GW170817.
Although only upper limits on gamma-ray emission are obtained, they correspond
to a luminosity of erg s in the GeV energy band
depending on the distance and the assumed time duration of each event, which is
approximately the order of luminosity of typical short gamma-ray bursts. This
implies there will be a favorable opportunity to detect high-energy gamma-ray
emission in further observations if additional gravitational wave events with
favorable geometry will occur within our field-of-view. We also show the
sensitivity of {\sl CALET} for gamma-ray transient events which is the order of
~erg\,cm\,s for an observation of 100~s duration.Comment: 12 pages, 8 figures, 1 table. Accepted for publication in
Astrophysical Journa
On-orbit Operations and Offline Data Processing of CALET onboard the ISS
The CALorimetric Electron Telescope (CALET), launched for installation on the
International Space Station (ISS) in August, 2015, has been accumulating
scientific data since October, 2015. CALET is intended to perform long-duration
observations of high-energy cosmic rays onboard the ISS. CALET directly
measures the cosmic-ray electron spectrum in the energy range of 1 GeV to 20
TeV with a 2% energy resolution above 30 GeV. In addition, the instrument can
measure the spectrum of gamma rays well into the TeV range, and the spectra of
protons and nuclei up to a PeV.
In order to operate the CALET onboard ISS, JAXA Ground Support Equipment
(JAXA-GSE) and the Waseda CALET Operations Center (WCOC) have been established.
Scientific operations using CALET are planned at WCOC, taking into account
orbital variations of geomagnetic rigidity cutoff. Scheduled command sequences
are used to control the CALET observation modes on orbit. Calibration data
acquisition by, for example, recording pedestal and penetrating particle
events, a low-energy electron trigger mode operating at high geomagnetic
latitude, a low-energy gamma-ray trigger mode operating at low geomagnetic
latitude, and an ultra heavy trigger mode, are scheduled around the ISS orbit
while maintaining maximum exposure to high-energy electrons and other
high-energy shower events by always having the high-energy trigger mode active.
The WCOC also prepares and distributes CALET flight data to collaborators in
Italy and the United States.
As of August 31, 2017, the total observation time is 689 days with a live
time fraction of the total time of approximately 84%. Nearly 450 million events
are collected with a high-energy (E>10 GeV) trigger. By combining all operation
modes with the excellent-quality on-orbit data collected thus far, it is
expected that a five-year observation period will provide a wealth of new and
interesting results.Comment: 11 pages, 7 figures, published online 27 February 201
- …